Study On The Sensing Characteristics Of A New Type Of Extrinsic Optical Fiber Fabry-perot Sensor

The extrinsic optical fiber Fabry-Perot sensor has the advantages of simple structure,high sensitivity and anti-electromagnetic interference,and it is widely used in the fields of deep well detection,partial discharge and building structure health monitoring.Firstly,the theory of extrinsic optical fiber Fabry-Perot sensor is introduced in this paper,we can draw the conclusion that the output interference spectrum is related to cavity length and reflectivity.The result of theoretical analysis is verified by Matlab simulation.In addition,the production and the demodulation methods of the traditional optical fiber EFPI sensor and the optical fiber EFPI sensor with coated palladium gold are introduced.Secondly,the temperature characteristics of the traditional optical fiber EFPI sensor and the optical fiber EFPI sensor with coated palladium gold are studied.According to the temperature sensing mechanism of optical fiber EFPI,the temperature theory are deduced and the temperature characteristics are derived.The platform of temperature experiment contrasting research system is set up,and comparative study of temperature are carried out.The experimental results show that the temperature sensitivity of the fiber EFPI sensor with short cavity is high,and the temperature sensitivity of cavity length 323 um fiber EFPI with coated palladium gold is 6.083pm/?,which can avoid the influence of temperature on its interference spectrum.Finally,the transverse load characteristic of traditional fiber EFPI sensors and fiber EFPI sensors with coated palladium gold are investigated.The simulation of the transverse load characteristics is carried out by the joint mechanics simulation of Solidworks,Hypermesh and ANSYS.The simulation results show that the EFPI with coated palladium gold is larger than that of the traditional fiber EFPI sensor under the same load.The transverse load experimental platform for transverse load comparison experiment is set up.The experimental results show that the short-cavity optical fiber EFPI sensor has higher transverse load sensitivity when the surface applied the same load,and the transverse load sensitivity of the cavity length of 323 um fiber EFPI with coated palladium gold is 40.83pm/g,which is consistent with the theoretical simulation.The optical fiber EFPI sensor with coated palladium gold proposed in this paper has the advantages of high lateral load sensitivity and temperature self-compensation,which provides the basis for later field deployment.